Preparation and Hydrosilylation Activity of a Molybdenum Carbonyl Complex That Features a Pentadentate Bis(imino)pyridine Ligand

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• 作者：Raja Pal ; Thomas L. Groy ; Amanda C. Bowman ; Ryan J. Trovitch
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：September 2, 2014
• 年：2014
• 卷：53
• 期：17
• 页码：9357-9365
• 全文大小：397K
• ISSN：1520-510X

文摘

Attempts to prepare low-valent molybdenum complexes that feature a pentadentate 2,6-bis(imino)pyridine (or pyridine diimine, PDI) chelate allowed for the isolation of two different products. Refluxing Mo(CO)₆ with the pyridine-substituted PDI ligand, ^PyEtPDI, resulted in carbonyl ligand substitution and formation of the respective bis(ligand) compound (^PyEtPDI)₂Mo (1). This complex was investigated by single-crystal X-ray diffraction, and density functional theory calculations indicated that 1 possesses a Mo(0) center that back-bonds into the 蟺*-orbitals of the unreduced PDI ligands. Heating an equimolar solution of Mo(CO)₆ and the phosphine-substituted PDI ligand, ^Ph2PPrPDI, to 120 掳C allowed for the preparation of (^Ph2PPrPDI)Mo(CO) (2), which is supported by a 魏⁵-N,N,N,P,P-^Ph2PPrPDI chelate. Notably, 1 and 2 have been found to catalyze the hydrosilylation of benzaldehyde at 90 掳C, and the optimization of 2-catalyzed aldehyde hydrosilylation at this temperature afforded turnover frequencies of up to 330 h^鈥?. Considering additional experimental observations, the potential mechanism of 2-mediated carbonyl hydrosilylation is discussed.